Certain esters of 4-hydroxy-2,9-dioxatricyclo[4.3.1.0.sup.3,7 ] decanes are disclosed in published German Pat. application No. 1,961,433 and U.S. Pat. No. 3,812,154, in which the hydroxyl or acyloxy radical that is joined to the carbon atom numbered 4 and a .beta. configuration. The radical is consequently represented as being attached to the carbon atom in the 4 position by a solid line, which differs from its epimer that is referred as having an .alpha. configuration and which is represented as being attached to the carbon atom in the 4 position by a dotted or broken line. These prior compounds possess nervous system depressant and vascular dilating activity and have the following formulae. ##STR2## in which R.sub.2 is hydrogen and R.sub.3 is hydroxyl or an acyloxy radical.